I currently have a 347 and am thinking about adding Edelbrock Pro Flo fuel injection and then going with twin turbos. With an 8.5:1 CR, how much boost could I run? It's for a street car.
I currently have a 347 and am thinking about adding Edelbrock Pro Flo fuel injection and then going with twin turbos. With an 8.5:1 CR, how much boost could I run? It's for a street car.
Thanks.
With an intercooler,...probably 12-15 lbs on pump gas with a conservative tune. But there's other qualifiers to this:
what's the specs on the cam? Overlap?
Piston rings?
Piston design? Forged?
Exhaust system?
etc.......
Oh yea,....
I have not had too much luck with the 347s under boost regarding reliability and longevity.
The 331 seems to be a much better platform to boost from.
Yeah, I know the 331 would be a better choice. The problem is that I already have a 347. I was just thinking about changing the pistons to drop the compression and changing the cam to work with fuel injection.
The new cam would be a 114 degree blower cam.
The bottom end is a CHP Street Fighter - Pro Street setup with forged pistons, rods and crank. There is also a main girdle for extra support.
No exhaust yet. My friend would be helping me fabricate the exhaust after the turbo setup.
So, do you think 12lbs of boost is a good amount for the street? Also, what size turbos would I want to go with?
12 lbs is PLENTY for the street.
Consider changing the cylinder heads to a larger cc combustion chamber to reduce compression, rather than going into the bottom end.
Vic jrs--70cc have done just this for me in the past.
As far as the turbocharger model, others would have more up-to-date info than me.
good luck and have fun!
There not all that different, you will be well off with the blower cam if you select your turbo corectly!
Rule of thumb is you cant run over 8 psi with out an intercooler on the street. So keep that in mind. The larger cc heads will cause more heat build up in the head and makes them more prone to detonation then a low compression bottom end. This is less of a problem with aluminum heads, but when you add in the boost you are adding alot of heat. Thats is just somthing to consider, I myself am going with a large chamber aluminum head and am not worried about it. On a 347 at 12psi you could easily make around 650 fwhp. Thats another thing to think about. I should make about 500fwhp with my 351w at 8psi. You can also use a thick copper head gasket to lower your compression. For every .01" of head gasket its like adding 1 cc of chamber volume. So if you had a .08" head gasket it would be like adding 8 cc to the head.